Enable shadow copy by default

Inspired by this report in Rider: [RIDER-130882](https://youtrack.jetbrains.com/issue/RIDER-130882): After I build and run in the IDE there are locks held on everything even after existing the program that prevent me or Ai Assistant/Junie from doing a dotnet clean/build.

Let's make the shadow copy the default mode? Need to investigate how it behaves in Visual Studio — if it's enabled by default as well, then this is an accepted practice and let's embrace it.

Start by locating the current shadow-copy configuration and determining how the plugin controls it. Compare its default behavior with Visual Studio, then verify that enabling shadow copy prevents locks after an IDE build and run and allows a subsequent clean/build.

Written by the indexing model from the issue text.